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[ciwstevie]

Hi,

I'm having a very simple problem it seems...but I could not figure out how it should work.
I want to use a calculator block to specify the isentropic efficiency of a turbine based on a correlation.
In this correlation the mass flow, the pressure change and the isentropic enthalpy change enters.
This means I need the following data:
mass flow - no problem
Inlet pressure - no problem
outlet pressure - no problem
inlet enthaply - no problem
isentropic outlet enthalpy - THERE IS MY PROBLEM

As this enthalpy is not associated to any stream as it is a theoretical value I cannot access it through the use of property sets. I would like to obtain it from my property method like that

isentropic outlet enthalpy = function (inlet entropy, outlet pressure)

but I have not found a way to implement this in Aspen.....
BUT THIS MUST BE POSSIBLE!!!

Of course I could simulate a turbine with isentropic efficiency of 1 under the same conditions first to obtain a stream containing the enthalpy I am looking for but this would be quite tedeous in my case.......

Thanks for any help in advance!

Stefan